I use the same debugger and it generally works fine. I only use SWCLK,SWDIO, GND, PWR. No RESET or UART.
I sometimes have difficulties flashing my XIAO MG24’s however. In my case the reason is generally caused by the low height of the female headers on the expansion board.
This allows for misalignment of the pogo-pins under the XIOA MG24.
Apart from that the 'MG24 and Expansion “team-up” seems quite solid. All connections and GPIO modules seem to work OK.
(I haven’t tried/used the SD Card interface)
Unfortunately the XIOA<->Expansion pin header doesn’t have an “alignment” option so it is possible to misalign placement of the XIOA when inserting it onto the Expansion Board.
Placing it one pin down (missing pins 1 and 14, and yes, I have done that!) could cause some (permanent) damage due to the placement of the XIAO’s GND and 3V3 underside - especially with the XIAO powered by USB.
3V3 from the expansion will be grounded if the Debug Adapter and XIAO’s USB are on the same circuit.
5V from the XIAO would be shorted to GND but USB current protect should come into play (if connected).
I’d think that if my XIAO Expansion Board (and its multiple buck and boost switching regulators) dies, it’s probably due to that.
In hindsight, the placement of the power pins on the XIAO’s in the current position on both the standard (castellated) and SMD programming pins is a recipe for disaster.
Just to note - in my “experience”.
- The acrylic case doesn’t help.
- The battery connector is Positive Connection.
- USB can be connected during flashing.
- Turning the “power to target” option on the Si-DBG1015A works fine as does all the associated software. Press and hold the “Power Switch” button for 3 seconds to engage the 3V3 supply.
Pressing it again reverts back to “target supplied” immediately.
If you send me the hex/bin file that you used when the failure occurred, I can try here - I have all the same equipment…